The present invention relates generally to integrated circuit designs, and more particularly to an oscillating buffer with single gate oxide devices.
Oscillators are often used in semiconductor technology for clock modules, logic gates, oscillating chips, and much more. A conventional oscillator contains a crystal attached with a pair of capacitors along with some initial resistance. The RC network of the capacitors and resistance can help to adjust the timing of the oscillator. An oscillating buffer is coupled, in parallel, to the crystal. A conventional oscillating buffer works like an inverter by producing an amplified, inversed output signal. The crystal, RC network and oscillating buffer provide a predetermined waveform at a predetermined frequency.
The conventional oscillating buffer uses thick-gate devices and a higher source voltage for a signal input of a higher voltage, such as an input/output (I/O) voltage for I/O circuitries of an integrated circuit. However, a thin-gate devices are used in the core circuit operating at a lower voltage. This results in an integrated circuit with thick-gate and thin-gate oxide devices. Since such dual-gate oxide devices require separate sets of masks for their own fabrication processes, the fabrication of the integrated circuit that includes the conventional oscillating buffer and core circuit is complicated and costly.
Desirable in the art of oscillating buffer designs is an oscillating buffer with single gate oxide devices that operate at a core voltage, thereby simplifying the fabrication process and the cost.